U.S. Pat. No. 5,5645,241 granted to Mathias et al on Oct. 15, 1996 entitled "Convergent End Effector" and U.S. Pat. No. 5,579,998 granted to Hall et al on Dec. 3, 1996 entitled "Method For Coating A Substrate With A Reinforced Resin Matrix" on which the inventor Jack G. Scarpa is a co-inventor and which these patents and this patent application are commonly assigned to USBI. Both of these references disclose a spray gun that utilized a nozzle that is designed to configure the spray emitted by the nozzle into an atomized convergent plume of liquid resin and targets the plume with reinforced filler material downstream of the nozzle to mix and wet the filler just prior to being applied to the surface of the substrate. In other words the reinforcing material is entrained around the atomized liquid resin flow and is caused to be captured thereby, mix therewith and become an homogeneously wetted coating material that after impact with the substrates becomes cured into a substantially reasonably thick coating exhibiting good strength and resistance characteristics. The gaseous transport stream together with the eductor deliver the ingredients in the proper proportions and the air stream for causing the atomization and mixing to provide the proper amounts of material to assure that the coating is uniform and consistent. Heating is applied in the proper sequence to assure that the viscosity is at the proper level to assure evenness of flow.
There are no commercially available or otherwise available spray systems that can convergently spray low VOC coatings with environmentally compatible fillers to roofs and other substrates requiring tough, water-resistant surfaces. I have found that I can provide a portable system that provides a tough, homogeneous low-VOC one or two part coating which is formed on the exterior of the spray gun's spray nozzle.
The unit is comprised of a portable cart which is capable of mixing and applying one or two-part coatings and a Class Five (non-uniform size/shape fibrous and flocculent) bulk solids with convergent spray technology process. The cart may be lifted to the roof, for example, by hoisting rings. Five or fifty-five gallon coating drums with low pressure barrel pump can remain at ground level. Drum pumps supply the coating components to the cart gear pumps that are controller based. The gear pumps supply fluid to the end of the spray gun where the resin is atomized and combined with dry materials at the convergent spray nozzle technology configuration. On the spray cart recycled dry materials, are supplied to a gravity fed hopper with a one or two-inch eductor and feed hopper tray. Dry compressed air supplied from the ground assists delivery of the filler material from the hopper through an eductor system to the spay gun or wand. The one or two-part acrylic or polyurethane coating is atomized as it exits the nozzle where in converges with fillers that may be of recycled materials to form a tough, homogenous, water-resistant coating. This portable system can also be utilizes as an application system for skid resistance coatings using either recycled rubber, aggregates or a combination for walkways, loading dock, recreational areas, etc.
Without intending to be a limitation to the scope of this invention, among the advantage of the present invention are the following:
1) portability/ease of application; PA1 2) resin and filler simultaneous in the convergent spray technology application; PA1 3) ability to protect several roof types with one method; PA1 4) significant reduction in waste and hazardous materials; PA1 5) use of recycled materials with no negative impact on the environment; PA1 6) highly loaded fillers that are characteristically inexpensive requires less resin which is an expensive ingredient; and PA1 7) capability of spraying one or two part resins and spray a variety of fillers with the same unit.